library(dplyr)
library(ggplot2)

assay_val = c(rnorm(500,10,2), rnorm(700, 5,1.5))
label = sample(c(0,1),1200,replace=TRUE)
label2 = c(rep(1,400),sample(c(0,1),400,replace=TRUE),rep(0,400))

library(pROC)
roc_rst = roc(label2~assay_val,plot=TRUE)

df_rst = data.frame(sen=roc_rst$sensitivities,spec=roc_rst$specificities,thres=roc_rst$thresholds)